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outpost ofastronomical endeavor。 slipher was unaware of einstein鈥檚 theory of relativity； and the worldwas equally unaware of slipher。 so his finding had no impact。
glory instead would pass to a large mass of ego named edwin hubble。 hubble was born in1889； ten years after einstein； in a small missouri town on the edge of the ozarks and grewup there and in wheaton； illinois； a suburb of chicago。 his father was a successful insuranceexecutive； so life was always fortable； and edwin enjoyed a wealth of physicalendowments； too。 he was a strong and gifted athlete； charming； smart； and immensely good…looking鈥斺�渉andsome almost to a fault；鈥潯n the description of william h。 cropper； 鈥渁n5named for johann christian doppler； an austrian physicist； who first noticed the effect in 1842。 briefly； whathappens is that as a moving object approaches a stationary one its sound waves bee bunched up as they cramup against whatever device is receiving them （your ears； say）； just as you would expect of anything that is beingpushed from behind toward an immobile object。 this bunching is perceived by the listener as a kind of pinchedand elevated sound （the yee）。 as the sound source passes； the sound waves spread out and lengthen； causing thepitch to drop abruptly （the yummm）。
adonis鈥潯n the words of another admirer。 according to his own accounts； he also managed tofit into his life more or less constant acts of valor鈥攔escuing drowning swimmers； leadingfrightened men to safety across the battlefields of france； embarrassing world…championboxers with knockdown punches in exhibition bouts。 it all seemed too good to be true。 it was。
for all his gifts； hubble was also an inveterate liar。
this was more than a little odd； for hubble鈥檚 life was filled from an early age with a levelof distinction that was at times almost ludicrously golden。 at a single high school track meetin 1906； he won the pole vault； shot put； discus； hammer throw； standing high jump； andrunning high jump； and was on the winning mile…relay team鈥攖hat is seven first places in onemeet鈥攁nd came in third in the broad jump。 in the same year； he set a state record for the highjump in illinois。
as a scholar he was equally proficient； and had no trouble gaining admission to studyphysics and astronomy at the university of chicago （where； coincidentally； the head of thedepartment was now albert michelson）。 there he was selected to be one of the first rhodesscholars at oxford。 three years of english life evidently turned his head； for he returned towheaton in 1913 wearing an inverness cape； smoking a pipe； and talking with a peculiarlyorotund accent鈥攏ot quite british but not quite not鈥攖hat would remain with him for life。
though he later claimed to have passed most of the second decade of the century practicinglaw in kentucky； in fact he worked as a high school teacher and basketball coach in newalbany； indiana； before belatedly attaining his doctorate and passing briefly through thearmy。 （he arrived in france one month before the armistice and almost certainly never hearda shot fired in anger。）in 1919； now aged thirty； he moved to california and took up a position at the mountwilson observatory near los angeles。 swiftly； and more than a little unexpectedly； hebecame the most outstanding astronomer of the twentieth century。
it is worth pausing for a moment to consider just how little was known of the cosmos at thistime。 astronomers today believe there are perhaps 140 billion galaxies in the visible universe。
that鈥檚 a huge number； much bigger than merely saying it would lead you to suppose。 ifgalaxies were frozen peas； it would be enough to fill a large auditorium鈥攖he old bostongarden； say； or the royal albert hall。 （an astrophysicist named bruce gregory has actuallyputed this。） in 1919； when hubble first put his head to the eyepiece； the number of thesegalaxies that were known to us was exactly one： the milky way。 everything else was thoughtto be either part of the milky way itself or one of many distant； peripheral puffs of gas。
hubble quickly demonstrated how wrong that belief was。
over the next decade； hubble tackled two of the most fundamental questions of theuniverse： how old is it； and how big？ to answer both it is necessary to know two things鈥攈owfar away certain galaxies are and how fast they are flying away from us （what is known astheir recessional velocity）。 the red shift gives the speed at which galaxies are retiring； butdoesn鈥檛 tell us how far away they are to begin with。 for that you need what are known as鈥渟tandard candles鈥濃�攕tars whose brightness can be reliably calculated and used asbenchmarks to measure the brightness （and hence relative distance） of other stars。
hubble鈥檚 luck was to e along soon after an ingenious woman named henrietta swanleavitt had figured out a way to do so。 leavitt worked at the harvard college observatory asa puter； as they were known。 puters spent their lives studying photographic plates ofstars and making putations鈥攈ence the name。 it was little more than drudgery by another name； but it was as close as women could get to real astronomy at harvard鈥攐r indeed prettymuch anywhere鈥攊n those days。 the system； however unfair； did have certain unexpectedbenefits： it meant that half the finest minds available were directed to work that wouldotherwise have attracted little reflective attention； and it ensured that women ended up with anappreciation of the fine structure of the cosmos that often eluded their male counterparts。
one harvard puter； annie jump cannon； used her repetitive acquaintance with thestars to devise a system of stellar classifications so practical that it is still in use today。
leavitt鈥檚 contribution was even more profound。 she noticed that a type of star known as acepheid variable （after the constellation cepheus； where it first was identified） pulsated witha regular rhythm鈥攁 kind of stellar heartbeat。 cepheids are quite rare； but at least one of themis well known to most of us。 polaris； the pole star； is a cepheid。
we now know that cepheids throb as they do because they are elderly stars that havemoved past their 鈥渕ain sequence phase；鈥潯n the parlance of astronomers； and bee redgiants。 the chemistry of red giants is a little weighty for our purposes here （it requires anappreciation for the properties of singly ionized helium atoms； among quite a lot else）； but putsimply it means that they burn their remaining fuel in a way that produces a very rhythmic；very reliable brightening and dimming。 leavitt鈥檚 genius was to realize that by paring therelative magnitudes of cepheids at different points in the sky you could work out where theywere in relation to each other。 they could be used as 鈥渟tandard candles鈥濃�攁 term she coinedand still in universal use。 the method provided only relative distances； not absolute distances；but even so it was the first time that anyone had e up with a usable way to measure thelarge…scale universe。
（just to put these insights into perspective； it is perhaps worth noting that at the time leavittand cannon were inferring fundamental properties of the cosmos from dim smudges onphotographic plates； the harvard astronomer william h。 pickering； who could of course peerinto a first…class telescope as often as he wanted； was developing his seminal theory that darkpatches on the moon were caused by swarms of seasonally migrating insects。）bining leavitt鈥檚 cosmic yardstick with vesto slipher鈥檚 handy red shifts； edwin hubblenow began to measure selected points in space with a fresh eye。 in 1923 he showed that a puffof distant gossamer in the andromeda constellation known as m31 wasn鈥檛 a gas cloud at allbut a blaze of stars； a galaxy in its own right； a hundred thousand light…years across and atleast nine hundred thousand light…years away。 the universe was vaster鈥攙astly vaster鈥攖hananyone had ever supposed。 in 1924 he produced a landmark paper； 鈥渃epheids in spiralnebulae鈥潯。╪ebulae；from the latin for 鈥渃louds；鈥潯as his word for galaxies）； showing that theuniverse consisted not just of the milky way but of lots of independent galaxies鈥斺�渋slanduniverses鈥濃�攎any of them bigger than the milky way and much more distant。
this finding alone would have ensured hubble鈥檚 reputation； but he now turned to thequestion of working out just how much vaster the universe was； and made an even morestriking discovery。 hubble began to measure the spectra of distant galaxies鈥攖he business thatslipher had begun in arizona。 using mount wilson鈥檚 new hundred…inch hooker telescopeand some clever inferences； he worked out that all the galaxies in the sky （except for our ownlocal cluster） are moving away from us。 moreover； their speed and distance were neatlyproportional： the further away the galaxy； the faster it was moving。
this was truly startling。 the universe was expanding； swiftly and evenly in all directions。 itdidn鈥檛 take a huge amount of imagination to read backwards from this and realize that it must therefore have started from some central point。 far from being the stable； fixed； eternal voidthat everyone had always assumed； this was a universe that had a beginning。 it mighttherefore also have an end。
the wonder； as stephen hawking ha